From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Bird Subject: [PATCH 5/5] logger: clarify non-update of w_off in do_write_log_from_user Date: Tue, 7 Feb 2012 18:34:28 -0800 Message-ID: <4F31DF34.8000205@am.sony.com> References: <4F31DC31.6040303@am.sony.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4F31DC31.6040303@am.sony.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Greg KH , linux-embedded , linux kernel , Brian Swetland , Dima Zavin , Andrew Morton Add comment to explain when w_off is not updated in case of failed second fragment copy to buffer. Signed-off-by: Tim Bird --- drivers/staging/android/logger.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/drivers/staging/android/logger.c b/drivers/staging/android/logger.c index 8d9d4f1..115d8ed 100644 --- a/drivers/staging/android/logger.c +++ b/drivers/staging/android/logger.c @@ -330,6 +330,12 @@ static ssize_t do_write_log_from_user(struct logger_log *log, if (count != len) if (copy_from_user(log->buffer, buf + len, count - len)) + /* + * Note that by not updating w_off, this abandons the + * portion of the new entry that *was* successfully + * copied, just above. This is intentional to avoid + * message corruption from missing fragments. + */ return -EFAULT; log->w_off = logger_offset(log, log->w_off + count); -- 1.7.2.3